Peugeot 106 XN Brake Bleed Problems

Hi, the offside rears brakes recently went on my Peugeot 106 Xn and after closer inspection it was the brake cylinder leaking.
I replaced this and the connecting pipe tubing as well as a new set of brake shoes for each back tyre.

I've now gone to bleed the offside rear brake system and there's a few bubbles of air that appear and then nothing. No brake fluid comes through although the resevior under the bonnett is full. All other tyres bleed fine except the drivers side rear.

Are tere any known problems/ fixes for this or any suggestions as to what it could be?

Thanks